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持続脳波モニタリング
2014/6/10
松井宏樹
目次
•
前回までの話。
2013/7/9、慈恵ICU勉強会、井澤先生による非痙攣性癲癇重積と持続脳波モニタリングに
ついてもう一度。
•
脳波のおさらい。
•
どのようにすればcEEGを実施しやすくできるか。
・誘導を減らす!
・トレンドを見る!
・異常波形を非専門家が認識する、CSAを使う
前回までの話
Crit Care Med 2013;41:1124-1132
2EVIEW!RTICLE
Continuous Electroencephalographic Monitoring
in Critically Ill Patients: Indications, Limitations,
and Strategies*
Raoul Sutter, MD1–4; Robert D. Stevens, MD1–5; Peter W. Kaplan, MBBS, FRCP2,4
Objective: #ONTINUOUS ELECTROENCEPHALOGRAPHY AS A BEDSIDE
MONITOROFCEREBRALACTIVITYHASBEENUSEDINARANGEOFCRITICALLY
ILLPATIENTS4HISREVIEWCOMPILESTHEINDICATIONSLIMITATIONSAND
STRATEGIESFORCONTINUOUSELECTROENCEPHALOGRAPHYINTHE)#5
Data Source:4HEAUTHORSSEARCHEDTHEELECTRONIC-%$,).%DATABASE
Study Selection and Data Extraction:2EFERENCESFROMARTICLESOF
SPECIALINTERESTWERESELECTED
Data Synthesis and Conclusion:%LECTROENCEPHALOGRAPHICALLYnDElNED SUPPRESSION IS ROUTINELY USED AS THE BASIS FOR TITRATION OF
PHARMACOLOGICTHERAPYINREFRACTORYSTATUSEPILEPTICUSANDINTRACRANIAL HYPERTENSION 4HE INCREASING USE OF CONTINUOUS ELECTROENCEPHALOGRAPHYREVEALSACLINICALLYUNDERAPPRECIATEDBURDENOF
EPILEPTIFORM AND EPILEPTIC ACTIVITY IN PATIENTS WITH PRIMARY ACUTE
NEUROLOGIC DISORDERS AND ALSO IN CRITICALLY ILL PATIENTS WITH ACQUIRED ENCEPHALOPATHY 3TATUS EPILEPTICUS IS REPORTED WITH CONTINUOUS ELECTROENCEPHALOGRAPHY IN TO OF PATIENTS WITH
ISCHEMICSTROKETOWITHTRAUMATICBRAININJURYTO
WITHSUBARACHNOIDHEMORRHAGETOWITHINTRACEREBRALHEMORRHAGEANDOFPATIENTSFOLLOWINGCARDIORESPIRATORY
ARREST 4HESE lGURES UNDERSCORE THE IMPORTANCE OF CONTINUOUS
ELECTROENCEPHALOGRAPHY IN THE CRITICALLY ILL 4HE INTERPRETATION OF
CONTINUOUSELECTROENCEPHALOGRAPHYINTHE)#5ISCHALLENGEDBY
ELECTROENCEPHALOGRAPHY ARTIFACTS AND THE FREQUENT SUBTLE DIFFERENCESBETWEENICTALANDINTERICTALPATTERNSCrit Care Med 2013;
n
Key Words: CONTINUOUS ELECTROENCEPHALOGRAPHIC MONITORING
ENCEPHALOPATHYNEUROCRITICALCARESEIZURESSTATUSEPILEPTICUS
C
and nonneurologic illnesses. Focal electroencephalographic
slowing may indicate ischemia, while global slowing suggests
encephalopathy; loss of electroencephalographic variability
•
「なぜ脳波の話か」→持続的脳波モニタリング（cEEG）のレビューがCCMに出た。
•
意識障害患者、脳
記録される。
•
その中には痙攣を伴わないてんかん（NCS）が含まれ、これは脳波でのみ診断が可能で
ある。
塞、頭蓋内出血、頭部外傷などでは、かなりの頻度でてんかん波が
ritically ill patients frequently acquire an acute alteration
of mental status, which may be caused by nonconvulsive
seizures or status epilepticus (SE). Continuous
前回までの話
cEEG
•  Con>nuous!electroencephalography!
!
• 
30
(24
)!
!
%
%
BIS%(Bispectral%index)%
前回までの話
てんかんの頻度
Crit Care Med 2013;41:1124-1132
TABLE 1. Occurrence Rates of Seizures and Status Epilepticus
those p
from sec
Occurrence Rates
a much
ity (27%
Status
it is the
Critical Illness
Seizures
References
Epilepticus
References
der rath
Nonneurologic ICU patients
4%–15%
5, 117
0.4%
117
which d
The prob
Ischemic stroke
5%
50
1%–10%
58, 112
nonconv
Subarachnoidal
4%–16%
65–69
10%–14%
64, 114
(NCSz)
hemorrhage
seizures
Intracerebral hemorrhage
10%–30%
52, 72–75
1%–21%
74–76
ies of co
Hypoxic-ischemic
5%–40%
98–101
30%
41
lepticus
encephalopathy
early tr
outcome
Traumatic brain injury
12%–50%
84
8%–35%
90, 113, 114
is limited
ing extra
てんかん発作
てんかん重積
to achieve seizure suppression or to manage elevated intracraStudies of NCSE in comatose ICU patients
nial pressure via electroencephalographic burst suppression. tory arrest (CRA) consistently indicate tha
While these are common practices in the ICU, the optimal primarily on the severity of anoxic brain dam
electroencephalographic endpoint and the duration of such any effect attributable to superimposed seizu
程度にばらつきはあるが、いずれの疾患においても
かなりの頻度でてんかん波が記録される。
ranting treatment is based on the assumption that certain types
of sustained ictal activity damage the brain. Animal models
demonstrating ictal damage (11) are flawed because the models imperfectly represent human brain function, and the lesions
inducing seizures and SE may themselves produce deficits. The
main challenge is distinguishing the effects of initial brain insult
from possible consequences of subsequent ictal activity (12). In
patients with brain trauma or with intracerebral hemorrhage
(ICH), NCSE or seizures increase the risk of death. In other settings, the effect of seizures or SE is less well established (Fig. 2).
One study found a 3% mortality after NCSE in epilepsy patients
who had subtherapeutic antiepileptic drug (AED) levels, while
AND THE CHALLENGES THEY PRESENT
IN ICU MANAGEMENT
Artifacts
Acquisition and interpretation of the ICU electroencephalography are compromised (18, 19) by a number of factors including
wounds or bandages that limit electroencephalography electrode
placement, as well as sweating, muscle activity, and movements
commonly seen in delirious or agitated patients. Electrical interference may occur from mechanical ventilators, machines for
renal replacement therapy, neuromonitoring apparatus, pumps,
and electronic beds. Routine 20- to 30-min electroencephalogCrit be
Care
Med
2013;41:1124-1132
raphy should
reviewed
for artifacts
before considering cEEG,
and efforts should be made to
produce artifact-free recordings.
前回までの話
Figure 1. Time elapsed between start of continuous electroencephalography (cEEG) monitoring and detection
of the first seizure in critically ill patients (n = 110). *Three of these nine patients had nonconvulsive seizures as
well. Reproduced with permission from Claassen et al (2).
•
Periodic Discharges and
Triphasic Waves
Periodic discharges (PDs) including (pseudo)periodic lateralized epileptiform discharges
(PLEDs) (Fig. 3A) (20), bilateral
independent
pseudoperiodic
lateralized discharges (21), generalized periodic epileptiform
discharges (Fig. 3B) (22), and
triphasic waves (TWs) (23–25)
are patterns often encountered
in ICU electroencephalography.
Definitions and clinical associations are given in Table 2. Some
authors maintain that PDs
represent interictal cortical/
#RITICAL#ARE-EDICINE
www.ccmjournal.org
cEEGによるモニタリングを開始し、初回のseizureを発見するまでの頻度
（n=110）。
•
seizuresのほとんどがnonconvulsiveである。
•
最初の24時間で、88％のseizureが発見できる。
1125
前回までの話
•  10K20!(
)! !
tenKtwenty!system!
–  19
!
– 
!
!
•  cEEG
電極がたくさん必要
or!
脳波自体難しいイメージ
前回までの話
•
→cEEGは必要であるが施行が困難である。
目次
•
前回までの話。
•
脳波のおさらい。
•
どのようにすればcEEGを実施しやすくできるか。
・誘導を減らす!
・トレンドを見る!
・異常波形を非専門家が認識する、CSAを使う
脳波のおさらいー脳波は何を計測しているか
•
頭皮においた電極の
直下にある大脳皮質
神経細胞の電気活動。
•
上向きがマイナスの
電位。
•
同じ興奮性入力でも
深さで向きが変わる。
脳波のおさらいー基礎律動の周波数
•
脳活性が低下すると同期し
て興奮し（高振幅徐化）、
逆に脳活性が亢進すると脱
同期すると考えられている
（周波数増加）。
•
周波数は脳波の判読で最も
注意すべき指標である。
脳波のおさらいー電極配置
・頭全体を10％、20％、20％、20％20％、10％で分割
・頭の大きさに関係なくほぼ一定部位に電極配置ができる．
・各電極間の距離をほぼ等しくできる．
・電極に対応する大脳の解剖学的部位が確認されている．
脳波のおさらいー健常脳波
•
閉眼安静覚醒時の健常脳波。
•
アーチファクトを鑑別するため
に眼電図（EOG）と心電図
（ECG）を同時に記録する。
•
3cmで1秒。定規を当てて3cm
分の波のピークを数えれば基礎
律動の周波数がわかる。
!
!
後頭部
•
後頭部優位のアルファ律動
（10Hz）
脳波のおさらいー突発波
脳神経細胞の過剰興奮を反映
•  CSE して、突発波が記録される。
NCSE
•
!
– •
– 
– 
– 
• 
•
spike!wave!
てんかんの診断価値の高い突
sharp!wave!
!
発波は棘波（spike）と鋭波
!
（sharp wave）。
)
(
棘徐波複合、鋭徐波複合は過
剰興奮とその後に誘発される
脱分極を表している。
脳波のおさらいー基礎律動の徐化
a
＊
•
burst-suppression:高振幅鋭波（a,b）とそ
の間の低電位脳波(＊)を周期的に反復する。
•
蘇生後脳症などで意識障害が重症化するとみ
られる。
•
深麻酔にした時にも認められる。（BISで30
以下程度）
•
平坦脳波（flat）
•
矢印は心電図。
•
脳死あるいは深麻酔（BIS 0）
b
目次
•
前回までの話。
•
脳波のおさらい。
•
どのようにすればcEEGを実施しやすくできるか。
・誘導を減らす!
・トレンドを見る!
・異常波形を非専門家が認識する、CSAを使う
①誘導を減らす
Neurocrit Care (2009) 11:411–416
DOI 10.1007/s12028-009-9248-2
TAKE NOTICE TECHNOLOGY
Seizure Detection with a Commercially Available Bedside
EEG Monitor and the Subhairline Montage
G. Bryan Young Æ Michael D. Sharpe Æ
Martin Savard Æ Eyad Al Thenayan Æ
Loretta Norton Æ Corrine Davies-Schinkel
Published online: 8 July 2009
! Humana Press Inc. 2009
市販のベッドサイド脳波モニター
でてんかんをみつける
Abstract
Introduction Availability of standard, continuous electroencephalography (cEEG) monitoring in ICU is very
limited, although commercially available 4-channel modules are present in many ICUs. We investigated the
sensitivity of such modules compared with the more
complete monitoring with a standard EEG system.
Methods Seventy patients at high risk of seizures in the
sensitivity of 39% and a specificity of 92% for detection of
spikes and PLEDs.
Conclusions The 4-channel EEG module has limited but
practical usefulness for seizure detection when standard
cEEG monitoring is not available.
Keywords Acute brain injury ! Seizures !
Continuous electroencephalography ! Subhairline montage
誘導を減らす
Seizure Detection with a Commercially Available
Bedside EEG Monitor and the Subhairline Montage
•
Introduction
ICUで使用できる持続脳波モニタリングの機器は非常に限られている。その中でも比較的よく使
われる4チャンネルのモニターを、国際10­20法を用いたスタンダードなモニターと比較した。
•
Methods
対象は内科系ICU・外科系ICU・てんかん病棟のいずれかに入室した、てんかん患者と急性頭部
外傷患者70人。患者には番号が割り付けられ4チャンネルの脳波モニターと19チャンネルの一
般的な脳波モニターがどちらも装着された。解析は別々に行われ、もう一方の解析結果を見る
ことができないようにした。
•
Analysis
脳波は以前より定義されている分類を用いて解析された。それぞれの脳波につき2人の解析者が
判読し、別の分類をした時には結論が得られるまで2人でレビューした。
S/5 EEG Module, M-EEG (rev. 01)
S/5TM EEG Headbox, N-EEG (rev. 01)
誘導を減らす
monitor, GE Healthcare, Helsinki, Finland) using skin
surface electrodes (Zipprep #186-0023, Aspect Medical
Systems, Inc., Norwood, MA) and a subhairline montage
[6] (Fig. 1). The recordings were coded by number
『Datex-Ohmeda』＝4-channel
Technical Reference Manual Slot
performed for seizure activity and epileptiform spike
PLED activity by constructing 2 9 2 tables as depicted i
Table 1.
Results
The diagnostic categories and EEG results are detailed i
Table 2. The study group consisted of 70 patients (2
females) with an average age of 53 ± 18 (range 20–85
years. The most common ICU admission diagnosis wa
metabolic disorder (e.g., organ failure/sepsis). Ninetee
(27%) patients were admitted to the ICU (14 patients) o
epilepsy unit (5 patients) with a primary diagnosis of se
zures. Seizures were detected in 31% (n = 22) of patient
using standard 16-channel XLTEK cEEG and only 15/2
of these seizures were detected using the Datex-Ohmeda
modular, bedside technology (sensitivity = 68%; 95%
confidence interval [95% CI] 45–86%). One of the Datex
Ohmeda recordings was interpreted as showing a seizur
when the XLTEK recording of the same patient did no
(specificity = 98%; 95% CI 89–100%. The positive pre
dictive value (PPV) of the Datex-Ohmeda system was 94%
Table 1 Calculation of sensitivity and specificity
XLTEK seizure
Datex-Ohmeda seizure
Sensitivity = a/(a + c)
Fig. 1 Placement sites of adhesive electrodes for SHM
Specificity = d/(b + d)
VS
All specifications are subject to change without notice.
Document No. 800 1011-1
June 2001
Datex-Ohmeda Inc.
3030 Ohmeda Drive
53707-7550 MADISON, WIS
USA
Tel. +1-608-221 1551,Fax +1-608-222 9147
www.us.datex-ohmeda.com
Datex-Ohmeda Division,
Instrumentarium Corp.
P.O. Box 900, FIN-00031
DATEX-OHMEDA, FINLAND
Tel. +358 10 394 11 Fax +358 9 146 3310
www.datex-ohmeda.com
© Instrumentarium Corp. All rights reserved.
『XLTEK』＝19-channel＝standard EGG
Yes
No
Yes
a
b
No
c
d
The Datex-Ohmeda system was positive for spikes or
PLEDs in only 12 of the 31 detected with the XLTEK
system (sensitivity = 39% (95% CI = 22–58%). Three
cases were false positive for spikes with the Datex-Ohmeda
system. The specificity for spikes or PLEDs was 92% (95%
CI 79–98%); PPV was 80% (95% CI 52–96%); and NPV
was 65% (95% CI 51–78%) (Table 4).
誘導を減らす
Seizure Detection with a Commercially Available
Bedside EEG Monitor and the Subhairline Montage
•
Result
Neurocrit Care (2009) 11:411–416
413
Table 3 Seizure detection
Discussion
Table 2 Diagnostic categories and seizure detection
Diagnosis (number of
cases)
XLTEKrecorded
seizures
Datex-recorded
seizures
Seizure disorder
(Epilepsy—19)
8
6 (1 false
positive)
Metabolic (organ failure/
sepsis—21)
2
2
Neurosurgical post-op
for tumor (8)
1
1
Trauma (4)
2
1
Cardiac arrest (4)
1
1
Ischemic stroke (5)
CNS infection (3)
4
1
2
1
Intracerebral hemorrhage
(2)
2
1
Drug intoxication (2)
1
1
CNS vasculitis (1)
0
0
Hypertensive
encephalopathy (1)
0
0
(95% CI 70–100%) and its negative predictive value (NPV)
was 87% (95% CI 75–95%). The net results are shown in
Table 3.
The failure of detection of seizures using the subhairline
montage was not related to location of seizures since in this
Standard EEG
positive
Standard EEG
negative
Total
theirs (sp
one is no
activity.
We di
the value
We concu
probabili
managem
not avail
convulsiv
the case i
feasible a
available
structures
the most
these stru
hairline a
Our study
demonstrated
the
Datex
positive
15 application of a1commercially 16
available,
bedside,
cEEG module,
using a 54
Datex
negative 4-channel
7
47
bipolar subhairline
montage,
Total
22 was capable of48detecting 68% 70
of seizures, as by standard EEG technology. The new
Datex bedside module with SHM; Standard EEG 18-channel
technology
facilitates
early digital
monitoring
of the brain in
recordings
with XLTEK
EEG machine
patients with acute brain injury and at high risk of seizures.
Kolls and Husain performed a study somewhat similar
to ours, using modifications of the subhairline montage by
reformatting standard digital EEG recordings and reading
結果をTable
2, Table 3にしめす。
them blindly, while comparing to standard montages [8].
26人の女性を含む70人の患者。最も多い入室理由は敗血
With respect to seizure and spike detection, not surprisingly, they concluded that the subhairline montage was
症を含む代謝性疾患の21人、次がてんかんの19人。
inferior to standard EEG for long-term ICU recordings, as
! the sensitivity of detecting seizures and spikes/PLEDs was
only 72 and 53%, respectively.
Our findings demonstrated
XLTEK(standard
EEG)では22人の患者がてんかんと診
sensitivity rates of 68 and 39%, for detection of seizures
断された。Datex（4-channel）ではそのうち15人の患
and spikes/PLEDs, respectively. However, there are some
者しかてんかんと診断できなかった。（感度68%）
important differences between their study and ours: (1)
they did not apply electrodes below the hairline (see
XLTEKではてんかんなしとされた1人の患者が、Datexで
Fig. 1), but used the 10-20 system of placement; (2) they
はてんかんありと診断されてしまった。（特異度
98％）
used standard commercial EEG equipment for recording,
rather than the bedside cEEG module used in our study.
Note that the Datex-Ohmeda module sampling rate is only
100 Hz, while standard EEG machines sampling rates are
over 200 Hz; the lower sampling rate makes identification
CT-compatible electr
require frequent/mult
誘導を減らす
should provide bett
Seizure Detection with a Commercially Available
Fig. 3 SHM tracing showing epileptiform spikes and EKG contamCEEG monitoring in
ination. ItMonitor
was often difficult
to differentiate
them, especially Montage
Bedside EEG
and
the between
Subhairline
in patient outcome.
with ectopic or irregular cardiac rhythms
突発派の検出
Table 4 Spike or PLEDs detection
Standard EEG
positive
References
Standard EEG
negative
Total
Datex positive
12
3
15
Datex negative
19
36
55
Total
31
39
70
1. Jordan KG. Neurop
intensive care unit. J
2. Claassen J, Mayer S
Detection of noncon
itoring in critically i
3. Young GB, Jordan K
sive seizures in the
monitoring: an inve
tality. Neurology. 19
4. Vespa PM, Miller C
D, et al. Nonconvul
brain injury result in
pressure and metabo
5. Vespa PM, Nenov V,
the intensive care un
Clin Neurophysiol S
6. Bridgers SL, Ebersol
epileptiform abnorm
7. Jasper HH. The 10
Federation. Electroen
8. Kolls BJ, Husain AM
tool for nonconvuls
In addition, having cEEG allows one to monitor the
effect of treatment, e.g., achieving an appropriate level of
• 棘波(spike)と周期性一側性てんかん形発射（PLEDs）
burst-suppression level of sedation/anesthesia for the
management of status epilepticus, thus preventing both
は31例中12例しか検出できなかった。（感度39％）
over-treatments, with prolonged sedation and hemodynamic instability, and/or under-treatment, with prolonged,
unrecognized nonconvulsive seizures/status epilepticus
• 3例は偽陽性であった。（特異度92％）
[11, 12]. When cEEG is not available, monitoring of adequate levels of therapy becomes an estimate at best.
Other technical challenges of cEEG in the ICU include
the type of scalp electrodes used. An electrode that is easily
誘導を減らす
てんかん波の例
Neurocrit Care (2009) 11:411–416
19チャンネル
•
•
Fig. 2 a Sequential frames of a seizure maximally expressed in the
同じてんかん波を2つの機器で記録した。
left posterior head (the odd numbered channels, e.g., involving
electrodes C3, P3, F7, T3, T5, and O1, are from the left hemisphere).
The first frame is on the left, the next the upper right and the third is
on the lower right. Note the evolutionary changes in morphology,
4チャンネル
amplitude, and frequency that characterize the seizure. b The
seizure recorded with SHM, using the same arrangement of sequ
frames as in a. The first and third channels are from th
hemisphere. Note that the evolutionary changes of the seizu
recognizable, but there is abundant EKG artifact
19チャンネルのものでは左の後頭葉から出現するてんかん波と局在がわかる。アーチ
Fig. 2 a Sequential frames of a seizure maximally expressed in the
left posterior head (the odd numbered channels, e.g., involving
ファクトも少ない。
electrodes C3, P3, F7, T3, T5, and O1, are from the left hemisphere).
The first frame is on the left, the next the upper right and the third is
• 4チャンネルのものでは局在は不明。またアーチファクトが大量にのってしまっている。
on the lower right. Note the evolutionary changes in morphology,
amp
seiz
fram
hem
reco
誘導を減らす
アーチファクトの例
Neurocrit Care (2009) 11:411–416
Fig. 3 SHM tracing showing epileptiform spikes and EKG contamination. It was often difficult to differentiate between them, especially
with ectopic or irregular cardiac rhythms
•
4チャンネルのものでは、棘波とアーチファクトの区別が難しい。
Table 4 Spike or PLEDs detection
•
Although the current te
no access to cEEG, we
improvements that wil
detection rate of seizu
suppression, and variou
better sampling rates, th
and EMG artifact, alarm
impedances, better elec
electronic algorithm to
zures/dysrhythmias and
treatment are needed. It
simplified EEG applian
CT-compatible electrode
require frequent/multiple
should provide better
CEEG monitoring in the
in patient outcome.
Standard EEG
sp＝棘波、X＝心電図アーチファクト
positive
Datex positive
12
References
Standard EEG
negative
3
Total
15
1. Jordan KG. Neurophysi
intensive care unit. J Cli
2. Claassen J, Mayer SA, K
誘導を減らす
Seizure Detection with a Commercially Available
Bedside EEG Monitor and the Subhairline Montage
まとめ
•
KollsとHusainの研究でもほぼ同様の感度・特異度であった（Kolls BJ, Husain
AM. Assessment of hairline EEG as a screening tool for nonconvulsive
status epilepticus. Epilepsia. 2007;48: 959‒65）。彼らはstandard EEGのほ
うが持続脳波モニタリングには適しているとしている。
•
しかし、てんかんの検査前確率が高い病態のとき、あるいは脳波検査がすぐできな
いときには4チャンネルの簡易脳波検査も有用だと考えられる。
•
4チャンネルのものでも特異度は高いため、異常波が捕まえられればてんかんであ
る可能性が高い。
•
その他にもてんかんの治療に際し、鎮静が深すぎないか、浅すぎないかの判断にも
用いることができる。
•
クリームを使った脳波用電極は6時間程度で剥がれ始めてしまうが、心電図用電極
などを用いれば48時間以上適切な記録がとれた。
②トレンドをみる
Friberg et al. Critical Care 2013, 17:233
http://ccforum.com/content/17/4/233
REVIEW
Clinical review: Continuous and simplified
electroencephalography to monitor brain recovery
after cardiac arrest
Hans Friberg*1,2, Erik Westhall2,3, Ingmar Rosén2,3, Malin Rundgren1,2, Niklas Nielsen2,4 and Tobias Cronberg2,5
Abstract
There has been a dramatic change in hospital care of cardiac arrest survivors in recent years, including the use of
target temperature management (hypothermia). Clinical signs of recovery or deterioration, which previously could
be observed, are now concealed by sedation, analgesia, and muscle paralysis. Seizures are common after cardiac
arrest, but few centers can offer high-quality electroencephalography (EEG) monitoring around the clock. This is due
primarily to its complexity and lack of resources but also to uncertainty regarding the clinical value of monitoring EEG
and of treating post-ischemic electrographic seizures. Thanks to technical advances in recent years, EEG monitoring
has become more available. Large amounts of EEG data can be linked within a hospital or between neighboring
hospitals for expert opinion. Continuous EEG (cEEG) monitoring provides dynamic information and can be used to
assess the evolution of EEG patterns and to detect seizures. cEEG can be made more simple by reducing the number
of electrodes and by adding trend analysis to the original EEG curves. In our version of simplified cEEG, we combine
心肺蘇生後の持続脳波モニタリング
トレンドをみる
Continuous and simplified electroencephalography to monitor brain
recovery after cardiac arrest
Introduction
•
低体温療法の発展もあり、心肺蘇生後の神経学的な回復は近年め
ざましいものがある。
•
復温にともない、てんかんや非痙攣性てんかん（NCS）がよく
起こるが、物品の不足やその煩雑性により脳波モニターができな
いことが多い。
•
より簡単に脳波をモニターするために、チャンネル数を2つに絞
り、amplitude-integrated EEG(aEEG)でトレンドをみてみる。
トレンドをみる
Continuous and simplified electroencephalography to monitor brain
recovery after cardiac arrest
Introduction
•
日の単位で脳波をモニターする場合、何らかの方法で脳波を定量
化し（qEEG）、時間軸を圧縮してトレンドを作る必要がある。
•
トレンドを見ることで、てんかんや基礎律動の変化を見つけやす
くする。
•
脳波を定量化する方法として、aEEGやCSAがあり、最近の脳波
計にはこれらのソフトが搭載されている。
•
今回は異常波も検出でき基礎律動の変化がわかりやすいaEEGに
ついてレビューする。
トレンドをみる
aEEGとは
トレンドをみる
aEEGとは
非対称フィルター
•
非対称フィルターがEEGの2Hz以下、25Hz以上の波形を除く。
•
2Hz以下は呼吸の影響、25Hz以上は筋電図と考える。
トレンドをみる
aEEGとは
半対数でスケール変更
•
臨床と関連深い低振幅域の感度を上げ、スケールを変更する。
トレンドをみる
aEEGとは
整流＋平滑化
•
マイナス方向のピークをプラス方向に変換する。
•
トレースを滑らかにし、ピークをなくす。
トレンドをみる
aEEGとは
•
1画面に4時間から6時間が表示できるように圧縮する。
•
同時に元の脳波波形も表示し、比較できるようにする。
Figure 1. Trend monitor displays original electroencephalography (EEG) and am
channels correspond to the left and right sides of the scalp. The aEEG timescale is com
is scanned by the interpreter for changes in background pattern or seizures, and detai
notes can be used to mark clinical events (for example, convulsions) to facilitate interp
Suppression periods with low amplitudes in the original EEG correspond to the lower
burst periods correspond to the upper border (aEEG maximum level).
トレンドをみる
aEEG
国際10­20法と比較して
6 hours
outcom
Early n
wake cy
hypothe
early a
pattern
recover
recover
treated
Figure 2. Example of a simplified electroencephalography
montage. Four recording electrodes in left frontal (F3), right frontal
(F4), left parietal (P3), and right parietal (P4) positions are shown with
ground (GND) and reference (REF) electrodes in the midline. The
original electroencephalography is displayed as two bipolar channels
(F3-P3, F4-P4), one on each side (red = left, blue = right).
•
脳波は右と左のみ。
•
monitoring procedure for assessment of brain maturity
脳波のことをある程度知っていれば必ずしも専門家が読
and asphyxia in newborns. aEEG recordings within
む必要はない。
•
ただし誘導が少ないため局所的な異常波をみつけるのは
苦手。
Seizure
epilept
An epil
and exc
Each se
is what
what is
are repo
after ca
in the
differen
of EEG
may or
http://ccforum.com/content/17/4/233
トレンドをみる（aEEG）
実際の画面
トレンド
4­6時間
元波形
10秒
Figure 1. Trend monitor displays original electroencephalography (EEG) and amplitude-integrated EEG (aEEG) from two channels. The
channels correspond to the left and right sides of the scalp. The aEEG timescale is compressed, showing 4 to 6 hours per screen. The aEEG trend
is scanned by the interpreter for changes in background pattern or seizures, and details are explored in the corresponding original EEG. Clinical
notes can be used to mark clinical events (for example, convulsions) to facilitate interpretation. In this display, a burst suppression pattern is shown.
Suppression periods with low amplitudes in the original EEG correspond to the lower border of the aEEG trends (aEEG minimum level), and the
burst periods correspond to the upper border (aEEG maximum level).
トレンドに変化があった時には、下に表示される元の波形を見る。
（burst-suppression pattern）
6 hours after birth have been shown to correctly predict
Friberg et al. Critical Care 2013, 17:233
トレンドをみる（aEEG）
http://ccforum.com/content/17/4/233
4つのパターンの紹介
Flat
予後は良くない
Page 5 of 9
基礎律動
予後は良い
Burst-suppression
殆どの場合予後は
良くない
てんかん重積
予後は様々
Figure 3. Four typical electroencephalography (EEG) patterns after cardiac arrest. (a) Flat. (b) Continuous background. (c) Burst suppression
(BS). (d) Electrographic status epilepticus (ESE). The arrows in the amplitude-integrated EEG timescales represent the corresponding original EEG
below.
Myoclonus is a common form of motor manifestation
in the comatose survivor of cardiac arrest and consists of
brief repetitive jerks, which may be irregular or rhythmic
ESE and a good outcome was described, and all had
preserved brain stem reflexes and a reactive EEG [29].
This group of patients may be similar or identical to those
aEEGでも波形の違いを読み取れる
Friberg et al. Critical Care 2013, 17:233
http://ccforum.com/content/17/4/233
トレンドをみる（aEEG）
Page 6 of 9
Friberg et al. Critical Care 2013, 17:233
http://ccforum.com/content/17/4/233
2種類のてんかん重積
Figure 4. Electrographic status epilepticus (ESE) evolving from a burst suppression (BS) pattern. (a) BS pattern (12 hours after cardiac arrest).
(b) BS pattern with short periods of repetitive epileptiform discharges (14 hours after cardiac arrest). (c) ESE with repeated electrographic seizures
(>1 Hz) for more than 30 minutes (16 hours after cardiac arrest).
•
Figure 5. Electrographic status epilepticus (ESE) evolving from a continuous background pattern. (a) Continuous background (45 hou
after cardiac arrest). (b) Onset (arrow) of repetitive epileptiform discharges (>1 Hz, >30 minutes), consistent with ESE (46 hours after cardiac arr
(c) Ongoing ESE (47 hours after cardiac arrest).
background pattern (Figure 5), and in this group
awakening and a good outcome [5,10]. A spontaneoussurvivors were reported [10,15].
and maintained burst suppression (BS) pattern after
cardiac arrest indicates that the prognosis is poor in mostPatient categorization based on evolution of the
[10], but not in all [5,23,51], cases. This discrepancyelectroencephalography
between studies might be related to different definitionsOur experience in the ICU is that comatose patients after
of BS since the development of a continuous backgroundcardiac arrest can be categorized into one of three main
activity usually proceeds through a phase of intermittentgroups. The three groups have different prognoses, and
cortical activity [57]. Our group has identified patientsthe use of cEEG is helpful in differentiating between
with two types of post-anoxic ESE, evolving fromthem. In addition to using the simplified cEEG with a
different background patterns; one develops early (typi-trend monitor, we use serial neurologic investigations
cally during hypothermia) and from a BS backgroundand biomarker measurements and tailor the use of
pattern (Figure 4). These patients had a uniformly pooradditional prognostic methods such as SSEP, routine
outcome. The other type of ESE develops late (typicallyEEG, and magnetic resonance imaging (MRI) on an
during or after rewarming) and from a continuous
Burst-suppression patternか
meticulous study using intermittent EEG, Jørgensen and
Holm [56] reported that cortical inactivity and a flat EEG
curve are common immediately after cardiac arrest and
that cortical activity eventually returns in most patients.
Studies using a simplified cEEG montage have shown
that initial cortical inactivity or a flat pattern (<10 µV) is
common during the early phase of hypothermia treatment after cardiac arrest but that it has no prognostic
significance [10,13]. On the other hand, persistence of
low-voltage or isoelectric patterns at 24 hours after the
arrest was found to be a strong indicator of poor prognosis [5]. Evolution from a non-continuous to a continuous background pattern during hypothermia or at the
time of normothermia is strongly associated with
•
予後が良くない。
•
The first group consists of comatose patients
mild or limited brain injury characterized by retur
continuous and reactive EEG pattern during hyp
mia. In this group, brain stem functions such as pu
and corneal reflexes usually return early, and p
recover motor response to pain as sedation wea
Levels of the brain damage biomarker neuron-s
enolase (NSE) are not elevated [15]. These patien
relatively easy to identify, and information to re
should be cautiously positive.
The second group consists of patients with severe
injury characterized by a flat or long-lasting BS
pattern, which often evolves into an ESE pattern
hypothermia (Figure 4), and still shows a malevole
基礎律動から発生したてんかん異
常波。
ら発生したてんかん異常波。
•
Pag
予後が良いものが報告されている。
トレンドをみる（aEEG）
Continuous and simplified electroencephalography to monitor brain
recovery after cardiac arrest
まとめ
•
単純化された脳波モニターは、心肺蘇生後において
てんかん異常波の検索に有用である。
•
aEEGは電極が少なく簡便であることと、トレンド
を見やすいことからマルチチャンネルの一般的な脳
波計よりもICUに適していると考えられる。
異常波形を非専門家が認識する（CSA）
③異常波形を非専門家が認識する
Neurocrit Care (2014) 20:32–39
DOI 10.1007/s12028-013-9912-4
ORIGINAL ARTICLE
Sensitivity of Compressed Spectral Arrays for Detecting
Seizures in Acutely Ill Adults
Craig A. Williamson • Sarah Wahlster •
Mouhsin M. Shafi • M. Brandon Westover
Published online: 20 September 2013
! Springer Science+Business Media New York 2013
Abstract
Background Continuous EEG recordings (cEEGs) are
increasingly used in evaluation of acutely ill adults. Prescreening using compressed data formats, such as compressed spectral array (CSA), may accelerate EEG review.
We tested whether screening with CSA can enable detection of seizures and other relevant patterns.
findings) for each record by exhaustive, page-by-page
review of the entire raw EEG.
Results Within each of the 39 cEEG recordings containing seizures, one CSA reviewer identified at least one
seizure, while the second CSA reviewer identified 38/39
patients with seizures. The overall detection rate was
89.0 % of 1,190 total seizures. When present, an average of
急性重症患者のてんかん
を見つけるCSAの感度
異常波形を非専門家が認識する（CSA）
Sensitivity of Compressed Spectral Arrays for
Detecting Seizures in Acutely Ill Adults
•
Background
急性期の重症患者へ持続脳波モニタリングが行われることが多くなってきた。プレ
スクリーニングで用いられるCSA（Compressed Spectral Array：圧縮スペクト
ル法）について検証してみた。
•
Methods
対象はMGHで持続脳波モニタリングが行われた18歳以上の患者113人。国際10-20
法に基づき19の電極で記録された。2時間の説明を受けた2人のレジデントがCSA
画面のみで判読した。一方で脳波判読の経験がある第三者がすべての元の脳波を解
析し、結果を照らし合わせる。
•
Results
113人のうち39人にてんかんが認められ、CSAを用いて98.7%のてんかん患者を同
定できた。また総数1190のてんかん異常波のうち、CSAで89％を同定できた。
異常波形を非専門家が認識する
CSA(Compressed Spectral Array)とは
まずフーリエ変換
Y軸：パワースペクトル
各周波数成分の出現量の指標
→
脳波に含まれている周波数がどの程度あるのか解析する
異常波形を非専門家が認識する
周波数スペクトル
CSAとは
これだけでは時間の情報がなくなってしまう。
↓
Z軸に時間をとり、重ねあわせ鳥瞰図の形にする。
CSA
displays may show several hours of data on a single
異常波形を非専門家が認識する（CSA）
page. This enables the electroencephalographer to identify ‘‘suspicious’’ regions of the EEG from their gross
features and then selectively ‘‘zoom in’’ on these regions
collection of 113 cEEG studies, using a
strategy designed to assess the sensitivity with
screening can be used to identify seizure
against gold-standard exhaustive visual review
Sensitivity of Compressed Spectral Arrays for
Detecting Seizures in Acutely Ill Adults
CSA：実際の画面
左側頭部
左傍矢状部
右側頭部
右傍矢状部
＊
5回のてんかんがあり
その内の太い矢印の波形
X軸 時間（2時間）
Y軸 周波数（0-20Hz）
Z軸 パワー（最低値：黒→青→緑→オレンジ→ピンク→白：最高値）
＊相対的に左のパワーが高い→青、相対的に右のパワーが高い→赤
異常波形を非専門家が認識する（CSA）
Sensitivity of Compressed Spectral Arrays for
Detecting Seizures in Acutely Ill Adults
CSA：アーチファクト
左
左
右
右
Fig. 1 Seizures and artifact in CSA displays. Compressed spectral
array (CSA) displays, demonstrating a seizure (a) and muscle artifact
(c). Each CSA displays 2 h of EEG data. x-axis time, y-axis frequency
(0–20 Hz), z-axis power with black representing lowest and white
highest power. From top-to-bottom, the individual segments represent: left lateral power (Fp1-F7, F7-T3, T3–T5, T5-O1), left
parasagittal power (Fp1-F3, F3-C3, C3-P3, P3-O1), right lateral
power (Fp2-F8, F8-T4, T4–T6, T6-O2), right parasagittal power
(Fp1-F4, F3-C4, C4-P4, P4-O2) and the relative asymmetry index.
For the relative asymmetry index, red represents increased right-sided
power and blue increased left-sided power. a Five seizures are
present, marked by arrows. b Section of the EEG corresponding to the
EEG segment marked by the thick arrow, demonstrating seizure
onset. c CSA display with several segments with muscle artifact, each
marked by an arrow corresponding to where a CSA reviewer placed a
mark. d Section of the EEG corresponding to the CSA segment
marked by the thick arrow, displaying muscle artifact (Color figure
online)
レジデントがてんかんありと判断し矢印した。
しかし実際は筋電図であった。CSAのみではその区別は難しい。
secondary generalization, and one patient had generalized
異常波形を非専門家が認識する（CSA）
status epilepticus. Diagnoses and demographic data for
the entire cohort and subdivided by seizure presence are
listed in Table 1. The average patient age was 59.6, and
approximately half were men. Fifty-eight percentage of
the continuous EEGs were recorded in an ICU and the
remainder on an acute neurological, medical, or surgical
ward.
seizures but had a lower false-positive rate, marking for
review a median of 5.4 and an average of 6.1 (SD 3.4)
segments per hour of cEEG, while correctly detecting an
average of 0.52 seizures per hour (SD 1.39). Consequently,
there was 1 seizure identified for every 11.7 segments
marked. Reviewer 2 marked a median of 7.5 and an
average of 8.6 (SD 5.8) segments per hour, while correctly
identifying 0.54 seizures per hour (SD 1.42), giving a false-
Sensitivity of Compressed Spectral Arrays for
Detecting Seizures in Acutely Ill Adults
Results：
Table 1 Patient Demographic Data
Age, mean ± SD (range)
All patients
(n = 113)
Patients without seizures
(n = 74)
Seizure patients
(n = 39)
59.6 ± 18.5 (19–95)
59.6 ± 18.6 (19–95)
59.6 ± 18.6 (23–88)
Male
58 (51.3 %)
38 (51.4 %)
20 (51.3 %)
ICU
66 (58.4 %)
47 (63.5 %)
19 (48.7 %)
21 (18.6 %)
16 (21.6 %)
5 (12.8 %)
7 (6.2 %)
6 (8.1 %)
1 (2.6 %)
TBI
CNS tumor
9 (8.0 %)
11 (9.7 %)
7 (9.5 %)
5 (6.8 %)
2 (5.1 %)
6 (15.4 %)
CNS infection/autoimmunity
11 (9.7 %)
7 (9.5 %)
4 (10.3 %)
Hypoxic–ischemic injury
8 (7.1 %)
4 (5.4 %)
4 (10.3 %)
Seizure disorder or spells
29 (25.7 %)
20 (27.0 %)
9 (23.1 %)
General medical disease
17 (15.0 %)
9 (12.2 %)
8 (20.5 %)
Diagnosis
ICH
Ischemic stroke
ICU intensive care unit; ICH intracranial hemorrhage; TBI traumatic brain injury; CNS central nervous system
Values are n (%) unless otherwise indicated
•
113人中39人にてんかんあり。一人につき1∼151のてんかん異常波が検出された。
123
•
約半分が男性。58.4％がICUで記録されている。
異常波形を非専門家が認識する（CSA）
Sensitivity of Compressed Spectral Arrays for
Detecting Seizures in Acutely Ill Adults
Results
36
Neurocrit Care (2014) 20:32–39
Table 2 Percentage of seizures and other patterns of interest identified and mean and median CSA review times
Reviewer 1
Reviewer 2
Combined
Sz pts identified (%)
38/39 (97.4)
39/39 (100)
98.7
Total szs identified (%)
1,039/1,190 (87.3)
1,080/1,190 (90.8)
89.0
Szs identified per pt, mean % (SD)
85.8 (20.8)
89.8 (15.8)
87.9 (18.4)
Szs identified per pt, median %
92.9
97.0
94.2
PEDs identified (%)
41/41 (100)
41/41 (100)
100
EDs identified (%)
64/67 (95.5)
62/67 (92.5)
94.0
RDA identified (%)
31/32 (96.9)
31/32 (96.9)
96.9
FS identified (%)
72/72 (100)
72/72 (100)
100
GS identified (%)
96/96 (100)
96/96 (100)
100
CSA review time, mean min (SD)
10.4 (5.0)
10.2 (5.8)
10.3 (5.4)
CSA review time, median min (range)
9.7 (1.5–25.0)
9.1 (1.6–42.2)
9.1 (1.5–42.2)
Data are number identified/total number (percent identified) unless otherwise specified
Sz seizure, pt patient, % percent, SD standard deviation, PEDs periodic epileptiform discharges, EDs epileptiform discharges, RDA rhythmic
delta activity, FS focal slowing, GS generalized slowing, CSA compressed spectral array, min minutes
•
判読者1は38/39人、判読者2は39/39人のてんかんを同定。
seizures in 2 of 17 patients using CSA, whereas at least one
positive rate of 15.7 segments marked per each seizure
（判読者1が見逃した患者は16秒の短いてんかん波が一度出現したのみであった。）
reviewer identified some seizures in all 17 patients using
identified. The combined average number of segments
aEEG. In the present study, a median of 94.2 % of seizures
marked per hour was 7.3 (SD 4.9). Across all subjects,
were identified per recording, while 38 of 39 patients with
there was an average of 0.53 (SD 1.4) seizures that were
• 1190のてんかん波のうち判読者1は1039（87.3％）、判読者2は1080（90.8%）のてんかん波を
seizures were identified by one reviewer and all 39 by the
successfully identified per hour. Thus, for every one seizure
同定できた。
other. The two reviewers identified 89.0 % of all 1,190
identified, there were 13.8 segments that did not contain
seizures that were present (overall false-negative rate of
seizures.
11.0 %). Earlier studies of the sensitivity of quantitative
• 判読にかかる時間は1患者あたり平均10.3分と短い。
異常波形を非専門家が認識する（CSA）
Neurocrit Care (2014) 20:32–39
見逃された波形の例
37
Fig. 2 Examples of seizures missed by CSA screening. Case 1 (a, b)
seizure lasting 83 s. This seizure was marked by reviewer 2 near the
a very focal right temporal seizure (onset marked by black arrows),
seizure onset (thick black arrow), but was ‘‘missed’’ by reviewer 2
lasting 20 s, with no significant change in the CSA background,
(thin black arrow) whose nearest CSA mark occurred 90 s after the
• A,B：右側頭葉起源のてんかん波で、持続時間は20秒。CSAではほとんど変化が見られず、2人とも見逃した。
missed by both reviewers. Case 2 (c, d) A right frontotemporal
end of the seizure
•
C,D：前頭側頭てんかん、持続時間83秒。これは同定されたが、その直後のてんかんが見逃された。
they could subsequently be ignored. This process of
segments is a simple and easily learned technique, which
異常波形を非専門家が認識する（CSA）
Sensitivity of Compressed Spectral Arrays for
Detecting Seizures in Acutely Ill Adults
まとめ
•
今回の研究ではスクリーニングを目的としているため、わざと偽陽性を許容した。その
ため高いてんかん波検出率（89.0%）となった。
•
レビュワーは一時間あたり平均7.3個のマークをしている。そのうち実際にてんかん波
であったものは一時間あたり平均0.53個で、ひとつのてんかん波を見つけるために間違っ
たマークを平均13.8個つけてしまっている。
•
今後レビュワーがCSAと元データを照らしあわせ、どれがアーチファクトか認識できる
ようになれば、偽陽性は減っていくものと思われる。
•
視覚的にどこにマークすればいいかわかりやすいため、初心者にも教えやすく、今後看
護師や技師にスクリーニングしてもらうこともできるだろう。
•
ただしてんかん患者が一人見逃されているということも心にとどめておかねばならない。
Neurocrit Care (2014) 20:32–39
33
Spectrograms, or compressed spectral arrays (CSA)
[17, 18], are the most widely used compressed data
format, consisting of three-dimensional plots with time
on the x-axis, frequency on the y-axis, and EEG power
on the z-axis (Fig. 1). Whereas standard EEG displays no
more than 10–15 s of data per screen and requires
simultaneous inspection of numerous channels, CSA
displays may show several hours of data on a single
page. This enables the electroencephalographer to identify ‘‘suspicious’’ regions of the EEG from their gross
features and then selectively ‘‘zoom in’’ on these regions
for more detailed review. However, the sensitivity of
CSA to detect clinically significant patterns, as compared
to standard exhaustive visual review, has never been
quantified.
We hypothesized that CSA could be used to screen
cEEG recordings for seizures and other clinically relevant
pathological patterns. This hypothesis was tested on a
collection of 113 cEEG studies, using a CSA review
strategy designed to assess the sensitivity with which CSA
screening can be used to identify seizures, compared
against gold-standard exhaustive visual review.
Fig. 1 Seizures and artifact in CSA displays. Compressed spectral
array (CSA) displays, demonstrating a seizure (a) and muscle artifact
(c). Each CSA displays 2 h of EEG data. x-axis time, y-axis frequency
(0–20 Hz), z-axis power with black representing lowest and white
highest power. From top-to-bottom, the individual segments represent: left lateral power (Fp1-F7, F7-T3, T3–T5, T5-O1), left
parasagittal power (Fp1-F3, F3-C3, C3-P3, P3-O1), right lateral
power (Fp2-F8, F8-T4, T4–T6, T6-O2), right parasagittal power
(Fp1-F4, F3-C4, C4-P4, P4-O2) and the relative asymmetry index.
For the relative asymmetry index, red represents increased right-sided
power and blue increased left-sided power. a Five seizures are
present, marked by arrows. b Section of the EEG corresponding to the
EEG segment marked by the thick arrow, demonstrating seizure
onset. c CSA display with several segments with muscle artifact, each
marked by an arrow corresponding to where a CSA reviewer placed a
mark. d Section of the EEG corresponding to the CSA segment
marked by the thick arrow, displaying muscle artifact (Color figure
online)
Discussion
Friberg et al. Critical Care 2013, 17:233
http://ccforum.com/content/17/4/233
Page 6 of 9
aEEG？
Figure 4. Electrographic status epilepticus (ESE) evolving from a burst suppression (BS) pattern. (a) BS pattern (12 hours after cardiac arrest).
(b) BS pattern with short periods of repetitive epileptiform discharges (14 hours after cardiac arrest). (c) ESE with repeated electrographic seizures
(>1 Hz) for more than 30 minutes (16 hours after cardiac arrest).
•
meticulous study using intermittent EEG, Jørgensen and
Holm [56] reported that cortical inactivity and a flat EEG
curve are common immediately after cardiac arrest and
that cortical activity eventually returns in most patients.
Studies using a simplified cEEG montage have shown
that initial cortical inactivity or a flat pattern (<10 µV) is
common during the early phase of hypothermia treatment after cardiac arrest but that it has no prognostic
significance [10,13]. On the other hand, persistence of
low-voltage or isoelectric patterns at 24 hours after the
arrest was found to be a strong indicator of poor prognosis [5]. Evolution from a non-continuous to a continuous background pattern during hypothermia or at the
time of normothermia is strongly associated with
CSA？
123
awakening and a good outcome [5,10]. A spontaneous
and maintained burst suppression (BS) pattern after
cardiac arrest indicates that the prognosis is poor in most
[10], but not in all [5,23,51], cases. This discrepancy
between studies might be related to different definitions
of BS since the development of a continuous background
activity usually proceeds through a phase of intermittent
cortical activity [57]. Our group has identified patients
with two types of post-anoxic ESE, evolving from
different background patterns; one develops early (typically during hypothermia) and from a BS background
pattern (Figure 4). These patients had a uniformly poor
outcome. The other type of ESE develops late (typically
during or after rewarming) and from a continuous
以前の研究ではaEEGとCSAを比較している。
（Stewart CP, Otsubo H, Ochi A, Sharma R, Hutchison JS, Hahn CD. Seizure identification in the
ICU using quantitative EEG displays. Neurology. 2010;75:1501‒8.）
aEEGで81％、CSAで83％のてんかん波を同定できたと
している。17のてんかん患者のうちaEEGではすべてで
てんかんを同定できたが、CSAでは2症例でてんかんを
同定できなかった。
•
どちらが優れているかはさらなる研究が必要と考えられ
る。
まとめ
•
重症患者が多いICUにおいて、もっと手軽に脳波をみたほ
うが良いのは間違いなさそう。
•
手軽にするためには1．誘導を減らす 2．長時間の記録
を短時間で読める工夫をする 3．専門家ではなくても読
めるようにする必要がある。
•
そのためにはaEEGやCSAなどの方法がある。
•
どちらが優れているか結論は出ていないが、まずはCSA
が搭載された機器が導入される様子。